/* 信息科技学习页面特定样式 - 浏览器兼容性增强 */

/* 浏览器兼容性重置 */
* {
    -webkit-box-sizing: border-box;
    -moz-box-sizing: border-box;
    box-sizing: border-box;
}

/* IE10+兼容性 */
@media screen and (-ms-high-contrast: active), (-ms-high-contrast: none) {
    .grade-filter-compact {
        -ms-flex-wrap: nowrap !important;
        flex-wrap: nowrap !important;
    }
    .filter-tabs {
        -ms-flex-wrap: nowrap !important;
        flex-wrap: nowrap !important;
    }
    .tab-btn {
        -ms-flex-direction: column;
        flex-direction: column;
        -ms-flex-align: center;
        align-items: center;
    }
    .current-info {
        -ms-flex-direction: column;
        flex-direction: column;
        -ms-flex-align: center;
        align-items: center;
    }
}

/* Safari特殊处理 */
@supports (-webkit-appearance: none) {
    .grade-filter-compact {
        -webkit-flex-wrap: nowrap !important;
        flex-wrap: nowrap !important;
    }
    .filter-tabs {
        -webkit-flex-wrap: nowrap !important;
        flex-wrap: nowrap !important;
    }
}

/* Firefox特殊处理 */
@-moz-document url-prefix() {
    .grade-filter-compact {
        display: -moz-box;
        -moz-box-orient: horizontal;
    }
    .tab-btn {
        display: -moz-box;
        -moz-box-orient: vertical;
        -moz-box-align: center;
    }
}

/* 页面头部 */
.page-header {
    background: linear-gradient(135deg, rgba(79, 172, 254, 0.95) 0%, rgba(0, 242, 254, 0.95) 100%);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    color: white;
    padding: 4rem 0;
    text-align: center;
    position: relative;
    overflow: hidden;
    margin-top: 0;
}

.page-header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
}

.page-header p {
    font-size: 1.2rem;
    opacity: 0.9;
}

.page-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: 
        radial-gradient(circle at 30% 30%, rgba(255,255,255,0.1) 0%, transparent 50%),
        radial-gradient(circle at 70% 70%, rgba(255,255,255,0.05) 0%, transparent 50%);
    animation: rotate 20s linear infinite;
    pointer-events: none;
}

.page-header::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 2px;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.5), transparent);
    animation: shimmer 2s ease-in-out infinite;
}

@keyframes shimmer {
    0%, 100% { transform: translateX(-100%); }
    50% { transform: translateX(100%); }
}

/* 导航激活状态 */
.nav a.active {
    background: rgba(255,255,255,0.2);
    padding: 8px 16px;
    border-radius: 20px;
    white-space: nowrap;
    font-size: 0.9rem;
}

/* Apple风格液体玻璃筛选器 */
.grade-filter-compact {
    margin-top: 2rem;
    display: -webkit-box !important;
    display: -ms-flexbox !important;
    display: flex !important;
    -webkit-box-pack: center;
    -ms-flex-pack: center;
    justify-content: center;
    -webkit-box-align: center;
    -ms-flex-align: center;
    align-items: center;
    gap: 1.5rem;
    -webkit-box-orient: horizontal;
    -webkit-box-direction: normal;
    -ms-flex-direction: row;
    flex-direction: row;
    -ms-flex-wrap: nowrap !important;
    flex-wrap: nowrap !important;
    width: 100%;
    max-width: 100%;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    min-height: 70px;
}

/* 强制单行显示，防止任何换行 */
@media (max-width: 360px) {
    .grade-filter-compact {
        gap: 0.5rem !important;
        padding: 0 0.5rem;
    }
    
    .filter-tabs {
        gap: 0px !important;
        padding: 1px !important;
    }
    
    .tab-btn {
        padding: 0.3rem 0.4rem !important;
        min-width: 45px !important;
        font-size: 0.75rem !important;
    }
    
    .current-info {
        min-width: 90px !important;
        padding: 0.3rem 0.6rem !important;
    }
}

.filter-tabs {
    display: -webkit-box !important;
    display: -ms-flexbox !important;
    display: flex !important;
    -ms-flex-wrap: nowrap;
    flex-wrap: nowrap;
    background: rgba(255, 255, 255, 0.08);
    /* 兼容性backdrop-filter */
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    -moz-backdrop-filter: blur(20px) saturate(180%);
    -ms-backdrop-filter: blur(20px) saturate(180%);
    /* 降级方案 */
    background-color: rgba(255, 255, 255, 0.15);
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: 25px;
    -webkit-border-radius: 25px;
    -moz-border-radius: 25px;
    padding: 6px;
    gap: 4px;
    /* 兼容性阴影 */
    box-shadow: 
        0 8px 32px rgba(0, 0, 0, 0.12),
        inset 0 1px 0 rgba(255, 255, 255, 0.2);
    -webkit-box-shadow: 
        0 8px 32px rgba(0, 0, 0, 0.12),
        inset 0 1px 0 rgba(255, 255, 255, 0.2);
    -moz-box-shadow: 
        0 8px 32px rgba(0, 0, 0, 0.12),
        inset 0 1px 0 rgba(255, 255, 255, 0.2);
}

.current-info {
    background: rgba(255, 255, 255, 0.08);
    /* 兼容性backdrop-filter */
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    -moz-backdrop-filter: blur(20px) saturate(180%);
    -ms-backdrop-filter: blur(20px) saturate(180%);
    /* 降级方案 */
    background-color: rgba(255, 255, 255, 0.15);
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: 20px;
    -webkit-border-radius: 20px;
    -moz-border-radius: 20px;
    padding: 0.8rem 1.5rem;
    /* 兼容性阴影 */
    box-shadow: 
        0 8px 32px rgba(0, 0, 0, 0.12),
        inset 0 1px 0 rgba(255, 255, 255, 0.2);
    -webkit-box-shadow: 
        0 8px 32px rgba(0, 0, 0, 0.12),
        inset 0 1px 0 rgba(255, 255, 255, 0.2);
    -moz-box-shadow: 
        0 8px 32px rgba(0, 0, 0, 0.12),
        inset 0 1px 0 rgba(255, 255, 255, 0.2);
}

.tab-btn {
    display: -webkit-box !important;
    display: -ms-flexbox !important;
    display: flex !important;
    -webkit-box-orient: vertical;
    -webkit-box-direction: normal;
    -ms-flex-direction: column;
    flex-direction: column;
    -webkit-box-align: center;
    -ms-flex-align: center;
    align-items: center;
    padding: 0.8rem 1.2rem;
    background: transparent;
    border: none;
    border-radius: 20px;
    -webkit-border-radius: 20px;
    -moz-border-radius: 20px;
    color: rgba(255, 255, 255, 0.7);
    cursor: pointer;
    /* 兼容性过渡 */
    transition: all 0.3s ease;
    -webkit-transition: all 0.3s ease;
    -moz-transition: all 0.3s ease;
    -o-transition: all 0.3s ease;
    min-width: 70px;
    white-space: nowrap;
    -ms-flex-negative: 0;
    flex-shrink: 0;
    /* 防止选中 */
    -webkit-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
    /* 触摸优化 */
    -webkit-tap-highlight-color: transparent;
}

.tab-btn.active {
    background: rgba(255, 255, 255, 0.2);
    color: white;
    box-shadow: 
        0 4px 20px rgba(255, 255, 255, 0.25),
        inset 0 1px 0 rgba(255, 255, 255, 0.3);
    transform: translateY(-1px);
}

.tab-btn:hover:not(.active) {
    background: rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.9);
}

.tab-number {
    font-size: 1.5rem;
    font-weight: 700;
    line-height: 1;
}

.tab-label {
    font-size: 0.8rem;
    margin-top: 0.2rem;
}

.current-info {
    display: -webkit-box;
    display: -ms-flexbox;
    display: flex;
    -webkit-box-orient: vertical;
    -webkit-box-direction: normal;
    -ms-flex-direction: column;
    flex-direction: column;
    -webkit-box-align: center;
    -ms-flex-align: center;
    align-items: center;
    -ms-flex-negative: 0;
    flex-shrink: 0;
    min-width: 120px;
}

.current-grade-text {
    color: white;
    font-size: 1.2rem;
    font-weight: 600;
    line-height: 1;
}

.current-subject {
    color: rgba(255, 255, 255, 0.8);
    font-size: 0.9rem;
    margin-top: 0.2rem;
}

/* Apple风格液体玻璃概览 */
.course-overview-compact {
    padding: 2rem 0;
    background: linear-gradient(135deg, #f8fafc 0%, #f1f5f9 100%);
    border-bottom: 1px solid rgba(226, 232, 240, 0.5);
}

.overview-stats {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 2rem;
    max-width: 600px;
    margin: 0 auto;
    padding: 2rem;
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 24px;
    box-shadow: 
        0 8px 32px rgba(0, 0, 0, 0.1),
        inset 0 1px 0 rgba(255, 255, 255, 0.2),
        inset 0 -1px 0 rgba(0, 0, 0, 0.05);
    position: relative;
    overflow: hidden;
}

.stats-card {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.stats-number {
    font-size: 2.5rem;
    font-weight: 700;
    color: #4facfe;
    line-height: 1;
}

.stats-label {
    font-size: 0.9rem;
    color: #64748b;
    margin-top: 0.2rem;
}

.stats-divider {
    width: 1px;
    height: 40px;
    background: linear-gradient(to bottom, transparent, #cbd5e1, transparent);
}

.stats-info {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.subject-name {
    font-size: 1.2rem;
    font-weight: 600;
    color: #1e293b;
    line-height: 1;
}

.grade-level {
    font-size: 0.9rem;
    color: #64748b;
    margin-top: 0.2rem;
}

/* 旧版年级筛选器样式保留但隐藏 */
.grade-filter {
    display: none;
}

.filter-label {
    color: rgba(255, 255, 255, 0.9);
    font-size: 1.1rem;
    font-weight: 500;
    margin-bottom: 1rem;
}

.filter-buttons {
    display: flex;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.filter-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 1rem 1.5rem;
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border: 2px solid rgba(255, 255, 255, 0.2);
    border-radius: 12px;
    color: white;
    cursor: pointer;
    transition: all 0.3s ease;
    min-width: 100px;
}

.filter-btn:hover:not(:disabled) {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
}

.filter-btn.active {
    background: rgba(255, 255, 255, 0.25);
    border-color: rgba(255, 255, 255, 0.5);
    box-shadow: 0 4px 20px rgba(255, 255, 255, 0.3);
}

.filter-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.grade-number {
    font-size: 2rem;
    font-weight: 700;
    line-height: 1;
}

.grade-text {
    font-size: 0.9rem;
    margin: 0.2rem 0;
}

.available {
    background: #4ade80;
    color: white;
    font-size: 0.7rem;
    padding: 2px 6px;
    border-radius: 10px;
    font-weight: 500;
}

.coming-soon {
    background: #f59e0b;
    color: white;
    font-size: 0.7rem;
    padding: 2px 6px;
    border-radius: 10px;
    font-weight: 500;
}

/* 当前年级信息 */
.current-grade-info {
    margin-top: 2rem;
    text-align: center;
}

.grade-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: rgba(255, 255, 255, 0.2);
    backdrop-filter: blur(10px);
    padding: 0.8rem 1.5rem;
    border-radius: 25px;
    border: 1px solid rgba(255, 255, 255, 0.3);
    margin-bottom: 0.8rem;
}

.badge-icon {
    font-size: 1.2rem;
}

.badge-text {
    color: white;
    font-weight: 600;
    font-size: 1rem;
}

.grade-description {
    color: rgba(255, 255, 255, 0.8);
    font-size: 0.95rem;
    margin: 0;
}

/* 课程概览 */
.course-overview {
    padding: 3rem 0;
    background: white;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

.section-header h2 {
    color: #333;
    font-size: 2.2rem;
    margin: 0;
}

.grade-indicator {
    display: flex;
    align-items: center;
}

.grade-tag {
    background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.overview-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
}

.overview-card {
    text-align: center;
    padding: 2rem;
    background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    color: white;
    border-radius: 15px;
    box-shadow: 0 5px 20px rgba(0,0,0,0.1);
    transition: transform 0.3s;
}

.overview-card:hover {
    transform: translateY(-5px);
}

.card-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.overview-card h3 {
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
    opacity: 0.9;
}

.overview-card .number {
    font-size: 2rem;
    font-weight: 700;
}

/* 年级内容容器 - 简化规则 */
.grade-content {
    display: none;
}

/* 激活的年级内容显示 */
.grade-content.active {
    display: block !important;
}

/* 简化的课程区域 */
.courses {
    padding: 2rem 0;
    background: #f8fafc;
}

/* 简化的课程卡片 */
.course-card {
    background: white;
    border-radius: 12px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    overflow: hidden;
    transition: all 0.3s ease;
    border: 1px solid #e2e8f0;
    opacity: 1;
    transform: translateY(0);
    min-height: 200px;
    display: flex;
    flex-direction: column;
}

.course-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    border-color: #cbd5e1;
}

.course-header {
    background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    color: white;
    padding: 1rem 1.2rem;
    display: flex;
    align-items: center;
    gap: 0.8rem;
}

.lesson-number {
    background: rgba(255, 255, 255, 0.2);
    padding: 0.2rem 0.6rem;
    border-radius: 12px;
    font-size: 0.8rem;
    font-weight: 600;
    flex-shrink: 0;
}

.course-header h4 {
    font-size: 1.1rem;
    font-weight: 600;
    margin: 0;
    line-height: 1.3;
}

.course-content {
    padding: 1rem 1.2rem;
    flex-grow: 1;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.course-content p {
    color: #475569;
    font-size: 0.9rem;
    line-height: 1.5;
    margin: 0;
    word-wrap: break-word;
    overflow-wrap: break-word;
}

.course-actions {
    padding: 0 1.2rem 1.2rem;
    margin-top: auto;
}

.course-actions .btn {
    width: 100%;
    justify-content: center;
    font-size: 0.9rem;
    padding: 0.8rem;
    border-radius: 8px;
}

.courses-header {
    text-align: center;
    margin-bottom: 3rem;
}

.courses-header h2 {
    font-size: 2.2rem;
    color: #333;
    margin-bottom: 1rem;
}

.courses-subtitle {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
}

.subtitle-text {
    color: #666;
    font-size: 1.1rem;
    font-weight: 500;
}

.other-grades-notice {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: #fff3cd;
    border: 1px solid #ffeaa7;
    padding: 0.8rem 1.5rem;
    border-radius: 25px;
    color: #856404;
}

.notice-icon {
    font-size: 1rem;
}

.notice-text {
    font-size: 0.9rem;
    font-weight: 500;
}

/* 简化的课程分类 */
.course-category {
    margin-bottom: 3rem;
}

.category-title {
    display: flex;
    align-items: center;
    font-size: 1.3rem;
    color: #1e293b;
    margin-bottom: 1.5rem;
    padding: 0.8rem 1.2rem;
    background: linear-gradient(135deg, #f1f5f9 0%, #e2e8f0 100%);
    border-radius: 12px;
    border-left: 4px solid #4facfe;
}

.category-icon {
    font-size: 1.3rem;
    margin-right: 0.8rem;
}

.course-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
}

/* 移除重复的课程卡片样式定义，避免冲突 */

/* 移除重复的course-header定义 */

.lesson-number {
    display: inline-block;
    background: rgba(255,255,255,0.2);
    padding: 4px 12px;
    border-radius: 15px;
    font-size: 0.9rem;
    font-weight: 500;
    margin-bottom: 0.5rem;
}

/* 移除重复的course-header h4定义 */

/* 移除重复的course-content定义 */

.course-meta {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
}

.duration, .difficulty {
    font-size: 0.9rem;
    color: #4facfe;
    font-weight: 500;
}

/* 特色练习按钮样式 */
.featured-exercise {
    background: linear-gradient(135deg, #ff6b6b 0%, #ee5a24 100%);
    color: white;
    font-weight: 600;
    box-shadow: 0 4px 15px rgba(255, 107, 107, 0.4);
    animation: pulse-glow 2s infinite;
    position: relative;
    overflow: hidden;
}

.featured-exercise:hover {
    background: linear-gradient(135deg, #ee5a24 0%, #ff6b6b 100%);
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(255, 107, 107, 0.6);
}

.featured-exercise::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
    transition: left 0.6s;
}

.featured-exercise:hover::before {
    left: 100%;
}

@keyframes pulse-glow {
    0%, 100% {
        box-shadow: 0 4px 15px rgba(255, 107, 107, 0.4);
    }
    50% {
        box-shadow: 0 4px 20px rgba(255, 107, 107, 0.6);
    }
}

.exercise-note {
    margin-top: 0.8rem;
    text-align: center;
    padding: 0.5rem;
    background: rgba(255, 107, 107, 0.1);
    border-radius: 8px;
    border-left: 3px solid #ff6b6b;
}

.exercise-note small {
    color: #666;
    font-size: 0.85rem;
    line-height: 1.4;
}

.exercise-info {
    margin-top: 0.8rem;
    text-align: center;
    padding: 0.6rem;
    background: rgba(79, 172, 254, 0.05);
    border-radius: 8px;
    border: 1px solid rgba(79, 172, 254, 0.1);
}

.exercise-info small {
    display: block;
    color: #64748b;
    font-size: 0.8rem;
    line-height: 1.4;
    margin-bottom: 0.3rem;
}

.backup-link {
    margin-top: 0.3rem;
}

.backup-link a {
    color: #4facfe !important;
    text-decoration: underline !important;
    font-weight: 500;
}

.backup-link a:hover {
    color: #0ea5e9 !important;
}

/* 学习资源 */
.learning-resources {
    padding: 3rem 0;
    background: white;
}

.learning-resources h2 {
    text-align: center;
    font-size: 2.2rem;
    margin-bottom: 3rem;
    color: #333;
}

.resources-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.resource-card {
    text-align: center;
    padding: 2rem;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-radius: 15px;
    box-shadow: 0 5px 20px rgba(0,0,0,0.1);
    transition: transform 0.3s;
}

.resource-card:hover {
    transform: translateY(-5px);
}

.resource-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.resource-card h3 {
    font-size: 1.3rem;
    margin-bottom: 1rem;
    font-weight: 600;
}

.resource-card p {
    opacity: 0.9;
    line-height: 1.6;
}

/* 空状态样式 */
.empty-state {
    text-align: center;
    padding: 4rem 2rem;
    background: white;
    border-radius: 15px;
    box-shadow: 0 5px 20px rgba(0,0,0,0.1);
}

.empty-icon {
    font-size: 4rem;
    margin-bottom: 1.5rem;
    opacity: 0.6;
}

.empty-state h2 {
    font-size: 2rem;
    color: #333;
    margin-bottom: 1rem;
}

.empty-state p {
    font-size: 1.1rem;
    color: #666;
    opacity: 0.8;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .page-header {
        padding: 2rem 0;
    }
    
    .page-header h1 {
        font-size: 1.8rem;
        line-height: 1.2;
        margin-bottom: 1.5rem;
        text-align: center;
    }
    
    /* 移动端简化筛选器 */
    .grade-filter-compact {
        gap: 1rem;
        flex-direction: row !important;
        flex-wrap: nowrap !important;
        align-items: center;
    }
    
    .filter-tabs {
        gap: 2px;
        padding: 3px;
    }
    
    .tab-btn {
        padding: 0.6rem 1rem;
        min-width: 60px;
    }
    
    .tab-number {
        font-size: 1.3rem;
    }
    
    .tab-label {
        font-size: 0.75rem;
    }
    
    .current-grade-text {
        font-size: 1.1rem;
    }
    
    .current-subject {
        font-size: 0.85rem;
    }
    
    /* 移动端简化概览 */
    .course-overview-compact {
        padding: 1.5rem 0;
    }
    
    .overview-stats {
        gap: 1.5rem;
        padding: 1.2rem;
        margin: 0 1rem;
    }
    
    .stats-number {
        font-size: 2rem;
    }
    
    .stats-label {
        font-size: 0.8rem;
    }
    
    .subject-name {
        font-size: 1.1rem;
    }
    
    .grade-level {
        font-size: 0.8rem;
    }
    
    /* 移动端年级筛选器 */
    .grade-filter {
        margin-top: 1.5rem;
    }
    
    .filter-label {
        font-size: 1rem;
        margin-bottom: 0.8rem;
    }
    
    .filter-buttons {
        gap: 0.8rem;
    }
    
    .filter-btn {
        padding: 0.8rem 1rem;
        min-width: 80px;
    }
    
    .grade-number {
        font-size: 1.5rem;
    }
    
    .grade-text {
        font-size: 0.8rem;
    }
    
    .available, .coming-soon {
        font-size: 0.65rem;
        padding: 1px 4px;
    }
    
    /* 移动端当前年级信息 */
    .current-grade-info {
        margin-top: 1.5rem;
    }
    
    .grade-badge {
        padding: 0.6rem 1.2rem;
        margin-bottom: 0.6rem;
    }
    
    .badge-text {
        font-size: 0.9rem;
    }
    
    .grade-description {
        font-size: 0.9rem;
        padding: 0 1rem;
    }
    
    /* 移动端概览区域 */
    .section-header {
        flex-direction: column;
        gap: 1rem;
        margin-bottom: 1.5rem;
    }
    
    .section-header h2 {
        font-size: 1.8rem;
    }
    
    .grade-tag {
        font-size: 0.8rem;
        padding: 0.4rem 0.8rem;
    }
    
    .course-overview {
        padding: 2rem 0;
    }
    
    .overview-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.5rem;
    }
    
    .overview-card {
        padding: 1.5rem;
    }
    
    .card-icon {
        font-size: 2rem;
        margin-bottom: 0.8rem;
    }
    
    .overview-card .number {
        font-size: 1.8rem;
    }
    
    .courses {
        padding: 2.5rem 0;
    }
    
    /* 移动端课程标题区域 */
    .courses-header {
        margin-bottom: 2rem;
    }
    
    .courses-header h2 {
        font-size: 1.8rem;
        margin-bottom: 0.8rem;
    }
    
    .courses-subtitle {
        gap: 0.8rem;
    }
    
    .subtitle-text {
        font-size: 1rem;
    }
    
    .other-grades-notice {
        padding: 0.6rem 1.2rem;
        margin: 0 1rem;
        text-align: center;
    }
    
    .notice-text {
        font-size: 0.85rem;
    }
    
    .course-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .course-card {
        border-radius: 15px;
    }
    
    .course-header {
        padding: 1.2rem;
    }
    
    .course-content {
        padding: 1.2rem;
    }
    
    .category-title {
        font-size: 1.5rem;
        margin-bottom: 1.5rem;
    }
    
    .category-icon {
        font-size: 1.8rem;
    }
    
    .learning-resources {
        padding: 2rem 0;
    }
    
    .resources-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .resource-card {
        padding: 1.5rem;
    }
    
    .resource-icon {
        font-size: 2.5rem;
        margin-bottom: 0.8rem;
    }
    
    /* 移动端导航优化 */
    .nav a.active {
        padding: 6px 12px;
        font-size: 0.85rem;
    }
    
    .nav ul {
        flex-wrap: nowrap;
        overflow-x: auto;
        -webkit-overflow-scrolling: touch;
        padding-bottom: 5px;
    }
    
    .nav li {
        flex-shrink: 0;
    }
}

@media (max-width: 480px) {
    .page-header {
        padding: 1.5rem 0;
    }
    
    .page-header h1 {
        font-size: 1.5rem;
        line-height: 1.1;
        margin-bottom: 1.2rem;
    }
    
    /* 小屏幕筛选器 */
    .grade-filter-compact {
        gap: 0.8rem;
        margin-top: 1.2rem;
        flex-direction: row !important;
        flex-wrap: nowrap !important;
    }
    
    .filter-tabs {
        gap: 1px;
        padding: 2px;
        flex-shrink: 0;
    }
    
    .tab-btn {
        padding: 0.4rem 0.6rem;
        min-width: 50px;
        font-size: 0.85rem;
    }
    
    .current-info {
        min-width: 100px;
        font-size: 0.85rem;
    }
    
    .tab-number {
        font-size: 1.2rem;
    }
    
    .tab-label {
        font-size: 0.7rem;
    }
    
    .current-grade-text {
        font-size: 1rem;
    }
    
    .current-subject {
        font-size: 0.8rem;
    }
    
    /* 小屏幕概览 */
    .course-overview-compact {
        padding: 1.2rem 0;
    }
    
    .overview-stats {
        gap: 1rem;
        padding: 1rem;
        margin: 0 0.5rem;
        flex-direction: column;
        text-align: center;
    }
    
    .stats-divider {
        width: 40px;
        height: 1px;
        background: linear-gradient(to right, transparent, #cbd5e1, transparent);
    }
    
    .stats-number {
        font-size: 1.8rem;
    }
    
    .stats-label {
        font-size: 0.75rem;
    }
    
    .subject-name {
        font-size: 1rem;
    }
    
    .grade-level {
        font-size: 0.75rem;
    }
    
    /* 小屏幕年级筛选器 */
    .grade-filter {
        margin-top: 1.2rem;
    }
    
    .filter-label {
        font-size: 0.95rem;
        margin-bottom: 0.6rem;
    }
    
    .filter-buttons {
        gap: 0.6rem;
    }
    
    .filter-btn {
        padding: 0.6rem 0.8rem;
        min-width: 70px;
    }
    
    .grade-number {
        font-size: 1.3rem;
    }
    
    .grade-text {
        font-size: 0.75rem;
    }
    
    .available, .coming-soon {
        font-size: 0.6rem;
        padding: 1px 3px;
    }
    
    /* 小屏幕当前年级信息 */
    .current-grade-info {
        margin-top: 1.2rem;
    }
    
    .grade-badge {
        padding: 0.5rem 1rem;
        margin-bottom: 0.5rem;
    }
    
    .badge-text {
        font-size: 0.85rem;
    }
    
    .grade-description {
        font-size: 0.85rem;
        padding: 0 0.5rem;
    }
    
    /* 小屏幕概览区域 */
    .section-header h2 {
        font-size: 1.6rem;
    }
    
    .grade-tag {
        font-size: 0.75rem;
        padding: 0.3rem 0.6rem;
    }
    
    .course-overview {
        padding: 1.5rem 0;
    }
    
    .overview-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }
    
    .overview-card {
        padding: 1.2rem;
    }
    
    .card-icon {
        font-size: 1.8rem;
        margin-bottom: 0.6rem;
    }
    
    .overview-card h3 {
        font-size: 1rem;
        margin-bottom: 0.4rem;
    }
    
    .overview-card .number {
        font-size: 1.6rem;
    }
    
    .courses {
        padding: 2rem 0;
    }
    
    /* 小屏幕课程标题区域 */
    .courses-header {
        margin-bottom: 1.5rem;
    }
    
    .courses-header h2 {
        font-size: 1.6rem;
        margin-bottom: 0.6rem;
    }
    
    .courses-subtitle {
        gap: 0.6rem;
    }
    
    .subtitle-text {
        font-size: 0.95rem;
    }
    
    .other-grades-notice {
        padding: 0.5rem 1rem;
        margin: 0 0.5rem;
        border-radius: 20px;
    }
    
    .notice-text {
        font-size: 0.8rem;
        line-height: 1.3;
    }
    
    .course-category {
        margin-bottom: 3rem;
    }
    
    .category-title {
        font-size: 1.3rem;
        margin-bottom: 1.2rem;
    }
    
    .category-icon {
        font-size: 1.5rem;
        margin-right: 0.8rem;
    }
    
    .course-header {
        padding: 1rem;
    }
    
    .course-header h4 {
        font-size: 1.2rem;
    }
    
    .lesson-number {
        font-size: 0.8rem;
        padding: 3px 10px;
    }
    
    .course-content {
        padding: 1rem;
    }
    
    .course-content p {
        font-size: 0.9rem;
        line-height: 1.5;
    }
    
    .course-meta {
        flex-direction: column;
        gap: 0.3rem;
        margin-bottom: 0.8rem;
    }
    
    .duration, .difficulty {
        font-size: 0.85rem;
    }
    
    /* 移动端特色练习按钮优化 */
    .featured-exercise {
        font-size: 0.9rem;
        padding: 12px 20px;
        width: 100%;
    }
    
    .exercise-note {
        margin-top: 0.6rem;
        padding: 0.4rem;
    }
    
    .exercise-note small {
        font-size: 0.8rem;
    }
    
    .learning-resources {
        padding: 1.5rem 0;
    }
    
    .learning-resources h2 {
        font-size: 1.8rem;
        margin-bottom: 2rem;
    }
    
    .resource-card {
        padding: 1.2rem;
    }
    
    .resource-icon {
        font-size: 2rem;
        margin-bottom: 0.6rem;
    }
    
    .resource-card h3 {
        font-size: 1.2rem;
        margin-bottom: 0.8rem;
    }
    
    .resource-card p {
        font-size: 0.9rem;
        line-height: 1.5;
    }
    
    .empty-state {
        padding: 3rem 1.5rem;
    }
    
    .empty-icon {
        font-size: 3rem;
        margin-bottom: 1rem;
    }
    
    .empty-state h2 {
        font-size: 1.6rem;
        margin-bottom: 0.8rem;
    }
    
    .empty-state p {
        font-size: 1rem;
    }
}